The invention relates to a method and device for transporting two flat objects. The objects are in particular flexible mail items, which are transported in a stacking compartment.
A sorting unit for flat flexible mail items transports every mail item fed to it and outputs it into one of a number of stacking compartments. The sorting unit transports the mail items in a specific initial direction. To remove those mail items which are to go into a specific stacking compartment, these mail items have to be diverted from the initial direction to a target direction.
A method and device for transporting two flat objects are known from EP 0915051 B1. This document describes how a continuous stream of overlapping mail items is produced. This continuous overlapping stream is diverted to the target direction and conveyed into a stacking compartment. Two successive mail items, which are transported into the same stacking compartment, overlap during transport in the target direction.
The drive rollers of the further conveyor belts operate in a start-stop mode with short switching times. The further conveyor belts must be tightly tensioned to transport the mail items reliably. The formation of the continuous overlapping stream functions as long as the mail items are sufficiently flat.
The method disclosed in the above mentioned EP 0915051 B1 reaches its limits when it is used in a sorting unit, which has to be able to sort mail items of very different thicknesses. In particular, thick overlapping mail items can no longer be transported by the two further conveyor belts. It appears to be technically impossible, or at least uneconomical to support a drive roller of a further conveyor belt in a movable manner, so that the distance between the two further conveyor belts can be changed.